Service stations are known in the field of ink jet franking machines for cleaning and capping a print head at a location beyond a printing station. In intervals between printing operations, the print head is moved beyond the printing station into the service station to be wiped or capped or both.
Generally the service station comprises a carriage that is movable transversally to the print head's path so as to bring the wiping device or the capping apparatus into engagement with the print head.
In U.S. Pat. No. 5,880,755 is disclosed a cleaning device for cleaning the outer surfaces of a row of ejection nozzles integrated in at least one print module of an ink jet print head of a postage meter having a base including a cleaning member for wiping the ink ejection surfaces, the cleaning member being mounted on a support member which is movable, by actuating a drive member which is linked to a connecting-rod and crank system, between a first position in which the cleaning member is remote from the print module and a second position in which the cleaning member has wiped the outer surfaces of the ejection nozzles. The cleaning member is mounted on one end of a sweeping hinged lever and includes a compensating support member, having respective springs, each carrying a set of independent wiping brushes, in order to transform the initial circular movement of the support member into a rectilinear movement of the brushes in contact with the ejection surfaces of the print module.
U.S. Pat. No. 6,464,326 relates to an apparatus for cleaning the nozzles of an ink jet cartridge that is mounted upon the carriage of a small point of sale printer. The carriage is arranged to carry one or more ink cartridges over a reciprocal path of travel through a printing station. The printer contains a drive roller mounted upon a shaft for advancing a substrate through the printing station. A rotor is journalled for free rotation on the shaft adjacent to one end of the drive roller. A rocker arm connects the rotor to a solenoid which when energized moves the rotor from an inoperative position into an operative position. A wiper blade is mounted upon the rotor which is adapted to wipe the nozzles on the ink cartridge when the rotor is in the operative position and to retract the blade out of contact with the nozzles when the rotor is moved into the inoperative position.
It is also known by U.S. Pat. No. 7,182,428 a device for cleaning the ink ejection nozzles of an inkjet printer head of a mail handling machine, comprising, on the one hand, a scraping means arranged in a path of travel of the mail items opposite the ink ejection nozzles and actuated by a mail item as it advances beneath the printer head, and, on the other hand, a means for cleaning this scraping means. Advantageously, the scraping means is articulated between a position of scraping in which the scraping means is arranged in the path of travel of the mail items, and a position of rest in which the scraping means is withdrawn from this path of travel.
Though the cleaning devices disclosed above could prove rather satisfactory under standard operating conditions, they do not prevent the print heads and their environment as well to get dirtier and dirtier with the unavoidable accumulation of ink particles over time or under industrial conditions.